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Highlights: A class of solvent-free covalent organic framework (COF) single-ion conductors (Li-COF@P) has been designed via ion–dipole interaction as opposed to traditional ion–ion interaction, promoting ion dissociation and Li+ migration through directional ionic channels. The Li-COF@P enabled long cycle life (88.3% after 2000 cycles) in all-solid-state Li organic batteries (ASSLOBs) under ambient operating conditions, which outperformed those of previously reported ASSOLBs. This Li-COF@P strategy holds promise as a viable alternative to the currently prevalent inorganic solid electrolytes. Single-ion conductors based on covalent organic frameworks (COFs) have garnered attention as a potential alternative to currently prevalent inorganic ion conductors owing to their structural uniqueness and chemical versatility. However, the sluggish Li+ conduction has hindered their practical applications. Here, we present a class of solvent-free COF single-ion conductors (Li-COF@P) based on weak ion–dipole interaction as opposed to traditional strong ion–ion interaction. The ion (Li+ from the COF)–dipole (oxygen from poly(ethylene glycol) diacrylate embedded in the COF pores) interaction in the Li-COF@P promotes ion dissociation and Li+ migration via directional ionic channels. Driven by this single-ion transport behavior, the Li-COF@P enables reversible Li plating/stripping on Li-metal electrodes and stable cycling performance (88.3% after 2000 cycles) in organic batteries (Li metal anode||5,5'-dimethyl-2,2'-bis-p-benzoquinone (Me2BBQ) cathode) under ambient operating conditions, highlighting the electrochemical viability of the Li-COF@P for all-solid-state organic batteries. [ABSTRACT FROM AUTHOR]

Current state‐of‐the‐art Li batteries use single‐phase electrolytes; however, these electrolytes often encounter difficulty in simultaneously fulfilling the nonidentical electrochemical requirements of cathodes and anodes. Here, a class of immiscible binary liquid electrolyte (BLE) is designed by starving free solvent molecules. Based on their electrochemical stability window, 1,2‐dimethoxyethane (DME) and succinonitrile (SN) are selected as model solvents for Li‐metal anodes and LiNi0.8Co0.1Mn0.1 (NCM811) cathodes, respectively. Li bis(fluorosulfonyl)imide (LiFSI), which promotes Li+ solvation (i.e., reduces free solvents), enables the phase separation of the miscible solvent mixture (SN−DME), and an increase in its concentration strengthens the coordination of Li+−FSI− in the solvation sheath, thus yielding (anion‐derived) fluorine‐rich electrode–electrolyte interphases. The resulting BLE allows 4.4 V Li‐metal full cells to exhibit a stable capacity retention under a constrained cell condition (Li (20 µm, 4.1 mAh cm−2)||NCM811 (3.8 mAh cm−2), N (negative)/P (positive) capacity ratio = 1.08), which exceed those of previously reported binary liquid electrolytes. [ABSTRACT FROM AUTHOR]

Despite the enormous interest in Li metal as an ideal anode material, the uncontrollable Li dendrite growth and unstable solid electrolyte interphase have plagued its practical application. These limitations can be attributed to the sluggish and uneven Li+ migration towards Li metal surface. Here, we report olefin‐linked covalent organic frameworks (COFs) with electronegative channels for facilitating selective Li+ transport. The triazine rings and fluorinated groups of the COFs are introduced as electron‐rich sites capable of enhancing salt dissociation and guiding uniform Li+ flux within the channels, resulting in a high Li+ transference number (0.85) and high ionic conductivity (1.78 mS cm−1). The COFs are mixed with a polymeric binder to form mixed matrix membranes. These membranes enable reliable Li plating/stripping cyclability over 700 h in Li/Li symmetric cells and stable capacity retention in Li/LiFePO4 cells, demonstrating its potential as a viable cationic highway for accelerating Li+ conduction. [ABSTRACT FROM AUTHOR]

Lithium metal batteries have higher theoretical energy than their Li-ion counterparts, where graphite is used at the anode. However, one of the main stumbling blocks in developing practical Li metal batteries is the lack of cathodes with high-mass-loading capable of delivering highly reversible redox reactions. To overcome this issue, here we report an electrode structure that incorporates a UV-cured non-aqueous gel electrolyte and a cathode where the LiNi0.8Co0.1Mn0.1O2 active material is contained in an electron-conductive matrix produced via simultaneous electrospinning and electrospraying. This peculiar structure prevents the solvent-drying-triggered non-uniform distribution of electrode components and shortens the time for cell aging while improving the overall redox homogeneity. Moreover, the electron-conductive matrix eliminates the use of the metal current collector. When a cathode with a mass loading of 60 mg cm−2 is coupled with a 100 µm thick Li metal electrode using additional non-aqueous fluorinated electrolyte solution in lab-scale pouch cell configuration, a specific energy and energy density of 321 Wh kg−1 and 772 Wh L−1 (based on the total mass of the cell), respectively, can be delivered in the initial cycle at 0.1 C (i.e., 1.2 mA cm−2) and 25 °C. The development of high energy lithium metal batteries is affected by the mass loading of the cathode. Here, the authors report a lithium metal pouch cell with a cathode capacity of 12 mAh cm-2. The positive electrode is prepared by applying UV-curable gel electrolyte as a processing solvent. [ABSTRACT FROM AUTHOR]

Despite their potential as post lithium‐ion batteries, solid‐state Li‐metal batteries are struggling with insufficient electrochemical sustainability and ambient operation limitations. These challenges mainly stem from lack of reliable solid‐state electrolytes. Here, a new class of single‐ion conducting quasi‐solid‐state soft electrolyte (SICSE) for practical semi‐solid Li‐metal batteries (SSLMBs) is demonstrated. The SICSE consists of an ion‐rectifying compliant skeleton and a nonflammable coordinated electrolyte. Rheology‐tuned SICSE pastes, in combination with UV curing‐assisted multistage printing, allow fabrication of seamlessly integrated SSLMBs (composed of a Li metal anode and LiNi0.8Co0.1Mn0.1 cathode) without undergoing high‐pressure/high‐temperature manufacturing steps. The single‐ion conducting capability of the SICSE plays a viable role in stabilizing the interfaces with the electrodes. The resulting SSLMB full cell exhibits stable cycling performance and bipolar configurations with tunable voltages and high gravimetric/volumetric energy densities (476 Wh kgcell−1/1102 Wh Lcell−1 at four‐stacked cells with 16.656 V) under ambient operating conditions, along with low‐temperature performance, mechanical foldability, and nonflammability. [ABSTRACT FROM AUTHOR]

The discovery of a reliable electrolyte system remains one of the key challenges for the development of advanced lithium–oxygen batteries. To date, no single electrolyte is verified to be stable and compatible with both the cathode (e.g., oxygen radicals, lithium peroxide, etc.) and anode (lithium metal) for lithium–oxygen batteries. In this work, a novel liquid‐based Janus electrolyte system consisting of two different immiscible liquid phases is proposed and it is demonstrated that this system is remarkably effective in promoting the sustainable operation of redox‐mediated lithium–oxygen batteries. The liquid‐based Janus electrolyte is rationally designed by considering its compatibility with the lithium–oxygen cell environment, the solubility difference of target soluble species, and the mutual immiscibility of the two liquid phases. By combining spectral characterization, a phase‐separation experiment, and in situ observation of the electrochemical cell, it is revealed that the liquid‐based Janus electrolyte suppresses the migration of redox mediators from one liquid phase to the other, thereby preventing the detrimental shuttle effect. The enhanced stability of redox mediation leads to improved cycling performance of the cell. The various combinations possible for the liquid‐based Janus electrolyte open a new unexplored pathway for the design of advanced electrolyte systems for lithium–oxygen batteries. [ABSTRACT FROM AUTHOR]

Despite the enormous potential of aqueous zinc (Zn)‐ion batteries as a cost‐competitive and safer power source, their practical applications have been plagued by the chemical/electrochemical instability of Zn anodes with aqueous electrolytes. Here, ionic liquid (IL) skinny gels are reported as a new class of water‐repellent ion‐conducting protective layers customized for Zn anodes. The IL skinny gel (thickness ≈500 nm), consisting of hydrophobic IL solvent, Zn salts, and thiol‐ene polymer compliant skeleton, prevents the access of water molecules to Zn anodes while allowing Zn2+ conduction for redox reactions. The IL‐gel‐skinned Zn anode enables sustainable Zn plating/stripping cyclability under 90% depth of discharge (DODZn) without suffering from water‐triggered interfacial parasitic reactions. Driven by these advantageous effects, a Zn‐ion full cell (IL‐gel‐skinned Zn‐anode||aqueous‐electrolyte‐containing MnO2 cathode) exhibits high charge/discharge cycling performance (capacity retention ≈95.7% after 600 cycles) that lies beyond those achievable with conventional aqueous Zn‐ion battery technologies. [ABSTRACT FROM AUTHOR]

Despite extensive research on flexible/wearable power sources, their structural stability and electrochemical reliability upon mechanical deformation and charge/discharge cycling have not yet been completely achieved. A new class of galvanically replaced single‐bodied lithium‐ion battery (LIB) fabric electrodes is demonstrated. As a proof of concept, metallic tin (Sn) is chosen as an electrode active material. Mechanically compliable polyethyleneterephthalate (PET) fabrics are conformally coated with thin metallic nickel (Ni) layers via electroless plating to develop flexible current collectors. Driven by the electrochemical potential difference between Ni and Sn, the thin Ni layers are galvanically replaced with Sn, resulting in the fabrication of a single‐bodied Sn@Ni fabric electrode (Sn is monolithically embedded in the Ni matrix on the PET fabric). Benefiting from the chemical/structural uniqueness and rationally designed bicontinuous ion/electron transport pathways, the single‐bodied Sn@Ni fabric electrode provides exceptional redox reaction kinetics and omnidirectional deformability (notably, origami‐folding boats), which lie far beyond those attainable with conventional LIB electrode technologies. [ABSTRACT FROM AUTHOR]

Abstract: A unique approach for improving the thermal stability of LiCoO2 cathode is presented, which is based on the treatment of LiCoO2 with ionic liquid (BDMIPF6, butyldimethylimidazolium-hexafluorophosphate), instead of traditional electrolyte modification. The electrolyte modification by the BDMIPF6 addition deteriorates the C-rate performances especially at high charge/discharge rates, with slightly improving the exothermic reaction between delithiated (charged) LiCoO2 and electrolytes. On the other hand, the BDMIPF6-modified cathode noticeably improves the thermal stability as well as little changes the C-rate performances. This is believed mainly due to the preferential location of BDMIPF6 in the LiCoO2 cathode rather than in the carbon anode, which might make it possible that the BDMIPF6 could effectively contribute to the suppression of exothermic reaction of delithiated LiCoO2 with electrolytes, with little affecting the electrolyte and the carbon anode. [Copyright &y& Elsevier]

Bulk‐type all‐solid‐state lithium batteries are highly promising candidates for large scale energy storage applications because of their superior safety. In article 1500865, Yoon Seok Jung and co‐workers demonstrate a strategy to obtain a dramatically improved performance by ensuring favorable ionic contacts. This is acheived via the addition of a small amount of solvate ionic liquids (Li(G3)TFSI), which demonstrate excellent compatibility with the sulfide solid electrolyte in composite electrodes. [ABSTRACT FROM AUTHOR]

• Li+ boosting molecular traps were synthesized by a novel morphology control of MOFs. • Semi-solid electrolytes with molecular traps were fabricated via one-step process. • Both ionic conductivity and Li+ transference number of electrolytes were improved. • Li+ boosting function of the molecular traps was elucidated via MD simulation. • Pouch-type semi-solid Li-metal cell was fabricated and operated at room temperature. Controlling electrostatic interactions between charged molecules is crucial to enabling advanced batteries with reliable lithium (Li)-ion conductors. To address this issue, herein, we present a class of morphology-controlled metal–organic frameworks (MOFs) that serve as Li+ boosting molecular traps for fast Li+ conduction. A rod-like MOF is incorporated into semi-interpenetrating polymer networks to construct Li+ boosting fluidic nanochannels, which enable fast Li+ transport (σ = 1.5 mS cm−1, t Li+ = 0.76) through the ionic pathway. Molecular dynamics simulations further elucidate the Li+ transport mechanism in these MOF-based molecular traps. This unusual Li+ conduction behavior of MOF-based semi-solid electrolytes suppresses the anion-triggered ion concentration gradient and facilitates the electrochemical reaction kinetics at the electrodes, ultimately improving the rate performance and cycling retention of Li-metal cells (consisting of LiNi 0.7 Co 0.2 Mn 0.1 O 2 cathodes and Li-metal anodes). Notably, a scalable pouch-type semi-solid Li-metal cell provides stable cycling performance for realistic batteries, exceeding those of previously reported Li batteries including porous crystalline frameworks. [ABSTRACT FROM AUTHOR]

Abstract: In a bid to develop a separator with improved thermal shrinkage that critically affects internal short-circuit failures of lithium-ion batteries, we demonstrate a new approach, which is based on introducing microporous composite coating layers onto both sides of a polyethylene (PE) separator. The composite coating layers consist of alumina (Al2O3) nanoparticles and polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP) gel polymer electrolytes. The microporous structure of the composite coating layers is considered a crucial factor governing the thermal shrinkage and electrochemical performance of the separators. The microporous structure is determined by controlling the phase inversion, specifically the solvent–nonsolvent miscibility, in the coating solutions. To quantitatively identify the effect of the solvent–nonsolvent miscibility, three different nonsolvents are chosen in the decreasing order of solubility parameter (δ) difference against the solvent (acetone, δ =20MPa1/2), which are respectively water (δ =48MPa1/2), butyl alcohol (δ =29MPa1/2), and isopropyl alcohol (δ =24MPa1/2). The microporous structure of the composite coating layers becomes more developed with the increase of not only the nonsolvent content but also the solubility parameter difference between acetone and nonsolvent. Based on this observation, we investigate the influence of the morphological variations on the thermal shrinkage and electrochemical performance of the composite separators. [ABSTRACT FROM AUTHOR]